Dandruff is caused by the growth of an organism that grows in excessively oily scalp resulting in itchy, greasy flaky scalp.
Avoid overnight application of oils, keep it to the minimum.
Do not use conditioners on the scalp, always keep them at a distance from your scalp.
If the dandruff is mild using anti-dandruff shampoos twice weekly or so will suffice.
If the dandruff is severe, certain oral medications wil get it under control.
Also certain other skin conditions can mimic dandruff,so a visit to a dermatologist will help you the best..